The present invention relates to the use of preceramic polymers as adhesives in the electronics industry. These adhesives form secure bonds between electronic components which are not subject to degradation.
Conventionally, electronic components have been interconnected with substrates such as carriers or circuit boards with metallic solders. Such solders are advantageous in that they form high strength bonds with excellent electrical and thermal conductivity. Moreover, such bonds can be formed quickly at a low cost.
The use of solder, however, has a number of drawbacks. For instance, solder is generally applied at high temperatures which can damage either the electronic component or the substrate. Moreover, the processes used for applying these solders are very sensitive such that temperature control, cleaning, fluxing, etc. are critical to prevent problems such as corrosion, weak joints, stress cracking and the like.
To overcome these problems, a number of polymer based alternatives have been suggested. They include materials such as epoxies, acrylic resins and silicones which can be filled with conductive particles and used to adhere electronic components to substrates. These polymers have he advantage of low temperature curing, simplified processing and they form strong, electrically conductive bonds which have fatigue and shock resistance.
The polymer alternatives have additional advantages and utilities in the electronic industry. For instance, unfilled polymers can be used as potting compounds to merely adhere large electrical components to the circuit board. Similarly, the polymers can be filled with materials that are excellent thermal conductors to distribute heat away from temperature sensitive devices.
The polymer alternatives, however, also have disadvantages. For instance, the polymer application techniques are sensitive to factors such as polymer concentration, solvent type, polymer temperature and the like. Moreover, the cure process which is necessary to harden polymers is sensitive to factors such as temperature, humidity, air concentrations and contaminants. Finally, the hardened polymers are often sensitive to the elevated temperatures seen in subsequent processing of the electronic component.
The use of preceramic polymers as adhesives is also known in the art. For instance, such polymers have been used to adhere a variety of materials such as plastics, ceramics and the like. It was not, however, known to use such materials to adhere electrical components to substrates.
The present inventors have now discovered that preceramic polymers can be used to form secure ceramic bonds between electronic components.